How do you implement inheritance and polymorphism in Python?

Inheritance in Python is achieved by defining a subclass that lists the parent class in parentheses. The subclass inherits attributes and methods from the parent and can override them or add new ones.

class Animal:
    def speak(self):
        return "..."

class Dog(Animal):
    def speak(self):
        return "Woof!"

Polymorphism allows objects of different classes to be treated as instances of a common superclass. In Python, this is often achieved through method overriding and duck typing. The Dog class overrides speak, so calling speak() on any Animal reference will execute the appropriate implementation.

Key points:

• Use super() to call parent class methods.
• Polymorphism is implicit; you don't need explicit interfaces.
• It promotes code reuse and flexibility.

Complexity is O(1) for method lookup in typical cases, but Python’s dynamic dispatch may add a small overhead compared to static languages.